The present invention relates to an optical switch, and specifically to an optical switch that controls the output of inputted light.
A further development of the information-oriented society involves building up an optical communication system that implements a high-speed transmission of a large-capacity of information. At present, the wavelength division multiplex (WDM) communication system has been developed, further accelerating the transmission speed of a network.
One of devices essential for a still faster optical communication system is a switching means of optical information. The conventional switching system of optical information required, at each relay point, a photoelectric transducer that converts optical information into electric information once and an electro-optic transducer that converts the electric information reversely into the optical information.
As the number of the relay points increases, the total power consumption of the photoelectric transducers and electro-optic transducers increases, and the switching speed decreases. Therefore, it is preferable to use an optical switch that switches the optical information directly in order to build up a still faster optical communication system.
As this type of optical switch, as disclosed in the “Nikkei Electronics” No. 8 issued on Jan. 29, 2000, the mechanical type switch, plane optical waveguide optical switch, mirror type optical switch, bubble type optical switch, and so forth have been examined up to now.
However, since the switching time of the conventional optical switch takes some millisecond, it is difficult to cope with the larger capacity and higher-speed for a future optical communication system. Also, the conventional optical switching system requires a high electric driving force for switching, and needs still higher energy consumption. As disclosed in the Japanese Patent Laid-open No. Hei 11-337988, an optical switch is proposed which attained a high-speed response by using a nonlinear optical material.
The optical switch disclosed in Japanese Patent Laid-open No. Hei 11-337988 arranges two nonlinear optical elements, and controls the switching by means of two different controlling lights; accordingly, the total size of the device becomes large. Therefore, it is difficult to miniaturize the optical switch for multi-channel switching. In addition, since the variation range of the refractive index is extremely small, the laser power for inducing the variation of about 2% of the refractive index is as high as about 5 to 50 MW/cm2, and the power consumption of the total device increases.